1. Field of the Invention
The present invention relates to a sheet feeding apparatus and a sheet sorting apparatus having such a sheet feeding apparatus, and more particularly, it relates to a sheet sorting apparatus which is connected to a copying machine having a reading apparatus, a facsimile machine (communication system), a printer connected to a computer, and a binding apparatus (stapler, glueing apparatus) to sort sheets or sheet bundles.
2. Related Background Art
In some conventional sheet or sheet bundle feeding apparatuses incorporated into a sheet sorting apparatus or an image forming apparatus, a thickness of a sheet bundle being fed is detected, and an upper roller is separated from a lower roller in accordance with the detected thickness so that the sheet bundle can be conveyed by the pair of upper and lower rollers.
However, in the above conventional case, since the thickness of the sheet bundle being fed must be detected and the upper roller must be separated from the lower roller in accordance with the detected thickness, the apparatus becomes very complex and expensive.